cas 120-89-8, PARABANIC ACID | Articles data

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Gas-solid reactions of single crystals: A study of reactions of NH 3 and NO2 with single crystalline organic substrates by infrared microspectroscopy
Reaction of single crystals of benzoic and trans-cinnamic acids with 200 Torr pressure of ammonia gas in a sealed glass bulb at 20 °C generates the corresponding ammonium salts; there is no sign of any 1:2 adduct as has been reported previously for related systems. Isotopic substitution using ND 3 has been used to aid identification of the products. Adipic acid likewise reacts with NH3 gas to form a product in which ammonium salts are formed at both carboxylic acid groups. Reaction of 0.5 Torr pressure of NO2 gas with single crystals of 9-methylanthracene and 9-anthracenemethanol in a flow system generates nitrated products where the nitro group appears to be attached at the 10-position, i.e. the position trans to the methyl or methoxy substituent on the central ring. Isotopic substitution using 15NO2 has been used to confirm the identity of the bands arising from the coordinated NO2 group. The products formed when single crystals of hydantoin are reacted with NO2 gas under similar conditions depend on the temperature of the reaction. At 20 °C, a nitrated product is formed, but at 65 °C this gives way to a product containing no nitro groups. The findings show the general applicability of infrared microspectroscopy to a study of gas-solid reactions of organic single crystals.
Jenkins, Samantha L.,Almond, Matthew J.,Atkinson, Samantha D.M.,Hollins, Peter,Knowles, John P.
p. 1131 - 1139
(2005)
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A facile synthesis of imidazolidine-2,4,5-trione
When glycoluril was oxidised with potassium persulfate, the main product was imidazolidine-2,4,5-trione. The structure of product was confirmed by IR, ESI, 1H NMR and X.ray crystal structure determination.
Yang, De-Li,Li, Jia-Rong,Lu, Hong-Yan,Zhang, Pan,Shi, Da-Xin
p. 625 - 626
(2014)
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THE MECHANISM FOR THE CONVERSION OF URIC ACID INTO ALLANTOIN AND DEHYDRO-ALLANTOIN. A NEW LOOK AT AN OLD PROBLEM
The reaction of uric acids 1 with iodine in alkaline solution yields, on acidification, new dehydroallantoins 11, or normal oxidation products, allantoins 13, depending on whether an excess or a stoichiometric amount of oxidant was used.The structure and regiochemistry of dehydro-allantoins 11 was established by chemical, spectroscopic, and 14C-labelling methods.These experimental results, in combination with other data, generate a new mechanistic scheme for the uricolytic pathway to allantoin, ruling out the intervention of a symmetrical transition state prior to the decarboxylation step.
Poje, M.,Sokolic-Maravic, Lea
p. 747 - 752
(1986)
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Denicke
p. 286,287
(1906)
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On-line electrochemistry/thermospray/tandem mass spectrometry as a new approach to the study of redox reactions: the oxidation of uric acid.
The electrochemical oxidation pathway of uric acid was determined by on-line electrochemistry/thermospray/tandem mass spectrometry. Intermediates and products formed as a result of electrooxidation were monitored as the electrode potential was varied. Several reaction intermediates have been identified and characterized by tandem mass spectrometry. The tandem mass spectrometric results provide convincing evidence that the primary intermediate produced during the electrooxidation of uric acid has a quinonoid diimine structure. The results indicate that once formed via electrooxidation, the primary intermediate can follow three distinct reaction pathways to produce the identified final products. The final electrochemical oxidation products observed in these studies were urea, CO2, alloxan, alloxan monohydrate, allantoin, 5-hydroxyhydantoin-5-carboxamide, and parabanic acid. The solution reactions that follow the initial electron transfer at the electrode are affected by the vaporizer tip temperature of the thermospray probe. In particular, it was found that at different tip temperatures either hydrolysis or ammonolysis reactions of the initial electrochemical oxidation products can occur. Most importantly, the results show that the on-line combination of electrochemistry with thermospray/tandem mass spectrometry provides otherwise difficult to obtain information about redox and associated chemical reactions of biological molecules such as the structure of reaction intermediates and products, as well as providing insight into reaction pathways.
Volk,Yost,Brajter-Toth
p. 1709 - 1717
(1989)
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Yao,Rusha
p. 2307,2309
(1979)
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Ozonization of thio- and azauracils
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Matsui,Kamiya,Kawamura,Shibata,Muramatsu
p. 2939 - 2941
(1989)
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Otsuji et al.
p. 4139,4149,4150
(1970)
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Uric Acid: A Less-than-Perfect Probe for Singlet Oxygen
Uric acid and/or its monoanion has long been used as chemical-trapping agents to demonstrate the presence of singlet oxygen, O2(a1Δg), in aqueous systems. “Oxidative bleaching” of uric acid, generally monitored through changes in the uric acid absorption spectrum, is often used in support of claims for the intermediacy of O2(a1Δg). The bleaching of uric acid has also been used to quantify photosensitized O2(a1Δg) yields in selected systems. Unfortunately, experiments performed to these ends often neglect processes and phenomena that can influence the results obtained. For the present study, we experimentally examined the behavior of uric acid under a variety of conditions relevant to the photoinitiated creation and subsequent removal of O2(a1Δg). Although the oxidative destruction of uric acid can indeed be a useful tool in some cases, we conclude that caution must be exercised such as not to incorrectly interpret the data obtained.
Bregnh?j, Mikkel,Dichmann, Lea,McLoughlin, Ciaran K.,Westberg, Michael,Ogilby, Peter R.
p. 202 - 210
(2019)
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Wake et al.
p. 2202,2205
(1971)
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(2,5-Dioxoimidazolidin-4-ylidene)aminocarbonylcarbamic Acid as a Precursor of Parabanic Acid, the Singlet Oxygen-Specific Oxidation Product of Uric Acid
Previously, we identified that parabanic acid (PA) and its hydrolysate, oxaluric acid (OUA), are the singlet oxygen-specific oxidation products of uric acid (UA). In this study, we investigated the PA formation mechanism by using HPLC and a time-of-flight mass spectrometry technique and identified unknown intermediates as (2,5-dioxoimidazolidin-4-ylidene)aminocarbonylcarbamic acid (DIAA), dehydroallantoin, and 4-hydroxyallantoin (4-HAL). DIAA is the key to PA production, and its formation pathway was characterized using 18O2 and H218O. Two oxygen atoms were confirmed to be incorporated into DIAA: the 5-oxo- oxygen from singlet oxygen and the carboxylic oxygen from water. Isolated DIAA and 4-HAL gave PA stoichiometrically. A plausible reaction scheme in which two pathways branch out from DIAA is presented, and the potential for PA as an endogenous probe for biological formation of singlet oxygen is discussed.
Iida, Sayaka,Yamamoto, Yorihiro,Fujisawa, Akio
(2019)
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Biltz,Kobel
p. 1822
(1921)
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Singlet dioxygen formation in ozone reactions in aqueous solution
In ozone reactions, singlet dioxygen [O2(1Δg)] is formed when ozone reacts by O-atom transfer. O2(1Δg) yields were determined for more than 50 compounds using as reference the reaction of hydrogen peroxide with hypochlorite. Close to 100percent yields were found in the reaction of O3 with sulfides, disulfides, methanesulfinic acid, and nitrite. In accordance with this, the only products are: methionine sulfoxide, methanesulfonic acid, and nitrate for the reaction of O3 with methionine, methanesulfinic acid, and nitrite, respectively. In the case of aliphatic tertiary amines (trimethylamine, triethylamine, and DABCO), the O2(1Δg) yields range between 70 and 90percent, the aminoxide being the other major product. With EDTA and nitrilotriacetic acid (NTA), the O2(1Δg) yield is around 20percent. The interpretation of the data with DABCO required the determination of the quenching constant of O2(1Δg) by this amine, kq = 1.8 × 109 dm3 mol-1 s-1 in H2O and D2O, two orders of magnitude lower than previously reported. Aromatic tertiary amines give even lower O2(1Δg) yields [N,N-dimethylaniline (7percent), N,N,N′,N′-tetramethylphenylenediamine (9percent)]. Substantial amounts of O2(1Δg) are also formed with the DNA model compounds, 2′-deoxyguanosine (40percent) and 2′-deoxyadenosine (15percent, in the presence of tert-butyl alcohol as ·OH scavenger). The pyrimidine nucleobases only yield O2(1Δg) when deprotonated at N(1). O2(1Δg formation is also observed with hydrogen sulfide (15percent), azide (17percent), bromide (56percent), iodide (12percent), and cyanide ions (20percent). The O2(1Δg yield from the reaction of O3 with phenols and phenolates is typically around 20percent, but may rise closer to 50percent in the case of pentachloro-and pentabromo-phenolate. Low O2(1Δg yields are found with unsaturated acids such as dihydroxyfumarate (6percent), muconate (2percent), and acetylenedicarboxylate (15percent). With saturated compounds, also, no O2(1Δg (e.g. with propan-2-ol, acetaldehyde, acetaldehyde dimethylacetal and glyoxal) or very little O2(1Δg (formic acid; 6percent, at high formate concentrations) was detected. As shown with some examples, knowledge of the O2(1Δg yield (in combination with that of other products) is a prerequisite for the elucidation of the mechanisms of O3 reactions in aqueous solutions.
Mun?oz,Mvula,Braslavsky,Von Sonntag
p. 1109 - 1116
(2001)
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Ogden
p. 2302
(1967)
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Cazeneuve
p. 834
(1899)
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Ishihara,Wang
p. 2307,2309
(1966)
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Study on reactions of 2-(dinitromethylene)-4,5-imidazolidinedione
Some new reactions of 2-(dinitromethylene)-4,5-imidazolidinedione (1) with water, alcohols, carboxylic acids, and alkalis were discovered. By reaction of 1 with carboxylic acids, large particle size 1,1-diamino-2,2-dinitroethylene (2) was prepared. By reaction of 1 with methanol, the methanol adduct (4) was synthesized and characterized. By reaction of 1 with water, the synthetic pathway of 2-methylimidazole to 2 could be achieved in a continuous process. By reaction of 1 with KOH, 2 and potassium dinitromethane (6) could be formed at different temperature, respectively. Compounds 1 and 4 decomposed into parabanic acid (5), losing nitrogen oxides and carbon oxides. Some explosive properties of 1 were studied. The mechanisms of synthesis of 1, 2, and 5 are discussed.
Cai, Huaqiang,Shu, Yuanjie,Huang, Hui,Cheng, Bibo,Li, Jinshan
p. 4369 - 4374
(2004)
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Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry
It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have s
Mattia Bizzarri, Bruno,Botta, Lorenzo,Pérez-Valverde, Maritza Iveth,Saladino, Raffaele,Di Mauro, Ernesto,García-Ruiz, Juan Manuel
p. 8126 - 8132
(2018/05/29)

A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide
The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818-12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225-256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249-1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746-2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657-662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are clearly specific, demonstrating that the mineral self-assembled membranes at the same time create space compartmentalization and selective catalysis of the synthesis of relevant compounds. Rather than requiring odd local conditions, the prebiotic organic chemistry scenario for the origin of life appears to be common at a universal scale and, most probably, earlier than ever thought for our planet.
Saladino, Raffaele,Botta, Giorgia,Bizzarri, Bruno Mattia,Di Mauro, Ernesto,Garcia Ruiz, Juan Manuel
p. 2806 - 2811
(2016/06/01)

Meteorites as catalysts for prebiotic chemistry
From outer space: Twelve meteorite specimens, representative of their major classes, catalyse the synthesis of nucleobases, carboxylic acids, aminoacids and low-molecular-weight compounds from formamide (see figure). Different chemical pathways are identified, the yields are high for a prebiotic process and the products come in rich and composite panels.
Saladino, Raffaele,Botta, Giorgia,Delfino, Michela,Di Mauro, Ernesto
p. 16916 - 16922
(2014/01/06)

Synthesis of pyrimidines and triazines in ice: Implications for the prebiotic chemistry of nucleobases
Herein, we report the efficient synthesis of RNA bases and func-tionalized s-triazines from 0.1 M urea solutions in water after subjection to freeze-thaw cycles for three weeks. The icy solution was under a reductive, methane-based atmosphere, which was s
Menor-Salvan, Cesar,Ruiz-Bermejo, Dra. Marta,Guzman, Marcelo I.,Osuna-Esteban, Susana,Veintemillas-Verdaguer, Sabino
experimental part
p. 4411 - 4418
(2009/12/07)

An unprecedented study of the rearrangement of 5,5-diazidobarbituric acids under various conditions
The unexpected parabanic acid derivatives 6a,b were obtained via unprecedented rearrangement of 5,5-diazidobarbituric acids 2a,b upon stirring in water at 50-60°C. Themolysis of diazides 2a,b in benzyl alcohol at 120-130°C afforded the tetrazole derivative 11 and/or benzyl allophanate 14.
Khattab, Ahmed F.,Kappe, Thomas
p. 609 - 611
(2007/10/03)

Improvement of a biomimetic porphyrin catalytic system by addition of acids.
The conditions of the use of the manganese/porphyrin/imidazole system needed to be improved in order to obtain larger amounts of models of metabolites. An increase of the oxidation yields and a better preservation of this catalytic system have been obtained on the examples of various alkanes, by an acid addition in the reaction mixture. Three manganoporphyrins were checked for evaluation of the reaction. These results were extended to molecules of therapeutical interest such as ibuprofen and phenylbutazone.
Segrestaa, Jerome,Verite, Philippe,Estour, Francois,Menager, Sabine,Lafont, Olivier
p. 744 - 748
(2007/10/03)

Synthesis and reactions of 1,1-diamino-2,2-dinitroethylene
Low temperature nitrations of 2-methylimidazole gave in addition to the known 2-methyl-5(4)-nitroimidazole (1), 2- (dinitromethylene)-5,5-dinitro-4- imidazolidinone (3) and parabanic acid (2). The tetranitro compound 3 was also obtained by nitration of 2-methyl-4,5-dihydro-(1H)-5-imidazolone (8). Thermal decomposition of 3 gave 2-(dinitromethylene)-4,5-imidazolidinedione (4) which also was the product from nitration of the new compound 2-methoxy- 2-methyl-4,5- imidazolidinedione. Treatment of 4 with aqueous ammonia gave the previously unknown 1,1-diamino-2,2-dinitroethylene (5). The physical properties and chemical behaviour of (5) are described.
Latypov, Nikolai V.,Bergman, Jan,Langtet, Abraham,Wellmar, Ulf,Bemm, Ulf
p. 11525 - 11536
(2007/10/03)

Gas/Solid Reactions with Nitrogen Dioxide
Numerous gas/solid reactions of nitrogen dioxide with organic substrates are investigated preparatively and mechanistically.Gaseous NO2 reacts with crystalline stable free radicals (nitroxyls 1, verdazyl 6) by electron transfer.The nitrite ions formed are irreversibly oxidized by NO2 via oxygen atom transfer.Solid cation nitrates are formed quantitatively.Thione bonds of thiohydantoins 8 are transformed to carbonyl bonds with formation of sulfur and NO presumably via nitrites as intermediates.Hydantoin 13 oxygenates at its free 5-methylene group via C-H abstraction and nitrite or it undergoes N-1 nitration via N-H abstraction depending on the conditions.Both reactions proceed quantitatively. 1,3-Oxazolidin-2-one (15) gives N-nitration and N-nitrosation with the NO produced.Nonenolized crystalline barbituric acids 17 are quantitatively nitrated (C-N bond formation with radicals) at their methylene groups. 4-Hydroxybenzaldehyde (19) and vanilline (22) give quantitative aromatic nitration (C-N bond formation with arenes) without melting.All possible regioisomers are formed.Solid 9-methylanthracene (26) gives a quantitative yield of its 10-nitro derivative 27.Crystalline anthracene (28) and gaseous NO2 yield 3 primary products 29 (cis; trans) and the new dimeric product 30 as well as the stable secondary products 31 and 32.The gas/solid tetranitration of tetraphenylethylene (33) is severely hindered by the water of reaction.However, a 95percent yield of pure tetrakis(p-nitrophenyl)ethylene is obtained if the drying agent MgSO4*2H2O is admixed and the product 34 extracted.The gas/solid procedures avoid solvents and fuming nitric acid.They give pure products without necessity for recrystallization in most cases and they avoid wastes.Atomic force microscopy (AFM) measurements on prominent faces of single crystals of 1a, 11a, 28, and 33 reveal phase rebuildings with well-directed long-range molecular transport.Nanoliquids were only present on (110) of 28.The characteristic AFM features are correlated with known X-ray crystal structure data and compared with previous results.The shape of the features depends on the molecular packing in the crystal bulk and on the molecular shapes.Molecular interpretations of the AFM features are given.
Kaupp, Gerd,Schmeyers, Jens
p. 5494 - 5503
(2007/10/02)

Oxidation chemistry of 2,8-dihydroxyadenine at a pyrolytic graphite electrode
The electrochemical oxidation of 2,8-dihydroxyadenine has been studied at a pyrolytic graphite electrode in the pH range 3.0-11.2.The oxidation of 2,8-dihydroxyadenine proceeds in a single 2e, 2H+ step to give the corresponding diimine, which on follow up chemical reactions gives allantoin at pH 7.5 and parabanic acid, alloxan and urea at pH 3.0.An EC mechanism for the electrochemical oxidation of 2,8-dihydroxyadenine has also been suggested.
Goyal, R. N.,Mittal, Alok
p. 852 - 856
(2007/10/02)

NITROIMIDAZOLONES. SYNTHESIS OF DEAZA ANALOGUES OF 3-NITRO-1,2,4-TRIAZOL-5-ONE
Analogues of 3-nitro-1,2,4-triazol-5-one (NTO) have been synthesized.The strategy revolves around a new method for the synthesis of imidazolones, namely the addition-elimination reaction of the sodium salt of trimethylsilylethanol with a trimethylsilylethoxymethyl (SEM)-protected dinitroimidazole followed by the acid-catalyzed conversion to the desired nitroimidazole (5).The N-methyl derivatives of 5 were prepared in a similar manner starting from the N-methyldinitroimidazoles.
Marlin, John E.,Killpack, Michael O.
p. 1385 - 1393
(2007/10/02)

PREPARATION AND SOME SIMPLE REACTIONS OF 1-SUBSTITUTED IMIDAZOLE-2,4,5-TRIONES
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Altural, Behzat,Akcamur, Yunus,Kollenz, Gert
p. 147 - 152
(2007/10/03)

Oxidation Chemistry of Adenine and Hydroxyadenines at Pyrolytic Graphite Electrodes
The electrochemical oxidation of adenine and hydroxyadenines has been studied in aqueous solutions in the pH range 3.0-11.2 using a pyrolytic graphite electrode.The initial course of the electrode reaction has been deduced to involve a 2e, 2H+ reaction to give 2- and not 8-hydroxyadenine, further oxidation of which gives 2,8-dihydroxyadenine and then diimine species which undergo a series of chemical reactions to give different products.The major products of oxidation at pH 3.0 and parabanic acid (imidazolidinetrione)> and at pH 7.0 have been isolated using HPLC and column chromatography and their structures elucidated by spectroscopic techniques.The probable EC mechanisms for their formation have also been suggested.
Goyal, Rajendra N.,Kumar, Anoop,Mittal, Alok
p. 1369 - 1375
(2007/10/02)

Ozonolyses of Cytosines and Guanine
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Matsui, Masaki,Shibata, Katsuyoshi,Muramatsu, Hiroshige,Nakazumi, Hiroyuki
p. 4987 - 4990
(2007/10/02)

Ozonolysis of Substituted Uracils
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Matsui, Masaki,Kamiya, Kazusaki,Shibata, Katsuyoshi,Muramatsu, Hiroshige
p. 1396 - 1399
(2007/10/02)

Pharmaceutical composition containing an imidazolidinetrione derivative or pharmaceutically acceptable salt thereof
Pharmaceutical compositions containing imidazolidinetrione derivatives or pharmaceutically acceptable salts thereof having hypoglycemic and hypolipidemic effects. The compositions comprise as an active ingredient at least one imidazolidinetrione derivative of the formula: STR1 wherein each of R1 and R2, which may be the same or different, is hydrogen, an alkyl group, a cycloalkyl group or STR2 and each of R3 and R4, which may be the same or different, is hydrogen, halogen, a nitro group, a lower alkyl group or a lower alkoxy group.
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(2008/06/13)

Photo-oxidation of Oxazolidones and Hydantoins in the Presence of Benzophenone
Irradiation in the presence of benzophenone and oxygen of nitrogen-containing heterocycles having an NCO group yields products arising out of regioselective oxidation α to the nitrogen atom.Direct irradiation (in the absence of benzophenone and oxygen) of 5-methyl- and 5,5-dimethyl-hydantoins yields allophanates.The first step of this reaction involves the homolysis of the C(4) - C(5) bond of the hydantoin.
Gramain, Jean-Claude,Remuson, Roland
p. 2341 - 2346
(2007/10/02)

The sonolysis of uracil
The sonolysis of uracil (1) has been studied at 630 kHz in the presence of air, oxygen, nitrogen and argon.The degradation products were identified by gc-ms analysis.Under aerated conditions the following products were found: uracil glycols (7), isobarbituric acid (8), N-formyl-N'-glyoxylurea (6), 5-hydroxyhydantoin (9), dialuric acid (10), alloxan monohydrate (12), parabanic acid (13), and oxaluric acid (14).In deaerated solutions 6, 13, and 14 were not observed but either 6-hydroxy-5,6-dihydrouracil (17) or its isomer (18) were detected in addition to 7, 8, 9, 10, and 12.The observed products have been used to develop a possible mechanism for the sonolytic degradation and the results are similar to those obtained in radiolysis.The sonolytic degradation of 5-bromouracil (19) is also reported: the products observed were 5-bromobarbituric acid (20), 12, 13, 14, and 9 and these can be rationalized by a similar mechanism scheme.
Yu, Tain-Jen,Sutherland, Ronald G.,Verrall, Ronald E.
p. 1909 - 1915
(2007/10/02)